1. Field of the Invention
The present invention relates to a hologram screen that is capable of regenerating an image by diffracting projected light.
2. Description of Related Art
A hologram screen that is capable of regenerating an image by diffracting projected light has been conventionally utilized, for example, for the purpose of displaying an advertisement on a shop window. As a versatile form of the above-mentioned hologram screens a screen formed by applying a hologram film to a resin plate with an adhesive has been known.
However, in the above-mentioned conventional hologram screen, the hologram film is exposed at its surface. Therefore, the hologram film may be separated from the resin plate, or may be scratched or otherwise damaged.
The resin plate may also be damaged. The above-mentioned hologram film is applied to the resin plate with an adhesive, and it is difficult to separate the hologram film from the resin plate without damaging the film. Therefore, when the resin plate is damaged, it is not possible to replace the resin plate with a new one to reuse the hologram film. Therefore, once the resin plate is damaged, the expensive hologram film has to be discarded. Further, when the hologram screen is leased, it is not possible to extend the rental use for a long period due to the above-mentioned problem.
It is an object of the present invention to overcome the aforementioned problem associated with the previous hologram screen and to provide a hologram screen which is capable of preventing separation and damage of the hologram film, and permits the hologram film to be reused easily, and which can be rented satisfactorily for a long period.
According to a first aspect of the invention, a hologram screen is provided which comprises a hologram film having the function of diffracting the light projected from a projector, and a first and a second transparent members which sandwich the hologram film so as to cover the film both from a front surface and from a back surface, characterized in that at least one of the first and the second transparent members is replaceable.
The most remarkable feature of the present invention is that the first and second transparent members sandwich the hologram film so as to cover same both from a front surface and from a back surface.
Terms, xe2x80x9cfront surfacexe2x80x9d and xe2x80x9cback surfacexe2x80x9d, are used herein only for convenience. As used herein, xe2x80x9cfront surfacexe2x80x9d means the surface on the side on which the first transparent member is located and xe2x80x9cback surfacexe2x80x9d means the surface on the side on which the above-mentioned second transparent member is located.
Next, the operative effect of the present invention will be described.
In the above-mentioned hologram screen, the first and second transparent members sandwich the hologram film so as to cover same between them.
Therefore, there is no risk of the hologram film separating from the first transparent member or from the second transparent member. also, the hologram film is protected from being damaged.
Further, even if the first or second transparent member is damaged, the hologram film can be released from the sandwiching by the first and second transparent members and the damaged transparent member may be replaced with a new transparent member to thereby reuse the hologram film.
As described above, in accordance with the present invention, a hologram screen is provided in which the hologram film can be protected from separation and damage, and can be easily reused.
Next, according to a second aspect of the present invention, the first and second transparent members are preferably fixed to each other with screws.
The hologram film can be thereby easily and securely sandwiched between the first and second transparent members. Since the first and second transparent members can be easily detached from each other, reuse of the hologram film is further facilitated.
Next, according to a third aspect of the present invention, the screws can fix the first and second transparent members to each other by penetrating a through hole provided in one of the first and second transparent members and being threaded into a sprue or threaded hole provided in the other.
The hologram film can be thereby easily and securely sandwiched between the first and second transparent members, and the reuse of the hologram film is further facilitated.
When above-mentioned sprue (HELI-SERT) is used, there is no risk of damage to the first and second transparent members even if the first and second transparent members are attached and detached frequently.
According to a fourth aspect of the present invention, the above-mentioned screws can fix the first and second transparent members to each other by penetrating a through-hole provided in both first and second transparent members and being threaded into a nut.
In this manner, also in this case, the hologram film can be easily and securely sandwiched between the first and second transparent members, and the reuse of the hologram film is further facilitated.
There is no risk of damage to the first and second transparent members even if the first and second transparent members are attached and detached frequently.
Next, according to a fifth aspect of the present invention, the first and second transparent members can be fixed to each other with an adhesive.
In this case, a hologram screen having a good appearance and design can be obtained.
Next, according to a sixth aspect of the present invention, the first and second transparent members can be fixed to each other with a clip or clips.
In this case, a hologram screen that allows a high operational efficiency in mounting and replacing of the first and second transparent members.
Next, according to a seventh aspect of the present invention, the first and second transparent members are preferably formed from a resin, a glass, or a plastic film.
A hologram screen capable of regenerating a high quality images can be thereby obtained cheaply.
When the first and second transparent members are formed from a resin, a light weight hologram screen can be obtained.
When the first and second transparent members are formed from a plastic film, a hologram screen that can be applied to a window pane as has been done previously is obtained.
The above-mentioned resin may include, for example, polycarbonate, acrylic resin, vinyl chloride resin, and the like.
Next, according to an eighth aspect of the present invention, an anti-sticking agent is preferably interposed between the hologram film and at least one of the first and second transparent members.
For example, when the front surface of the hologram film and the first transparent member are of such a material property that they are likely to stick to each other, the above-mentioned anti-sticking agent is interposed between the front surface of the hologram film and the first transparent members. When the back surface of the hologram film and the second transparent member are of such a material property that they are likely to stick to each other, the above-mentioned anti-sticking agent may be interposed between the back surface of the hologram film and the second transparent members.
With such a construction, a gap is created between the hologram film and the first or second transparent member, and sticking of the hologram film to the first or second transparent member can be prevented. Degradation of image quality due to local sticking between the hologram film and the first or second transparent member can be thereby prevented. Also, in the state in which images are not being regenerated, the good design and appearance of the hologram screen can be maintained.
Next, according to a ninth aspect of the present invention, the aforementioned hologram film is comprised of a hologram layer that has the function of diffracting the light projected from a projector and a PET layer that has the hologram layer applied on at least one of the surfaces thereof and having a hard coat formed thereon. The above-mentioned anti-sticking agent is preferably interposed between the above-mentioned PET layer and at least one of the first and second transparent members.
With such a construction, the surface of the hologram film having a hard coat formed thereon can be prevented from sticking to the first or second transparent member.
Next, according to a tenth aspect of the present invention, the hologram film can be constructed such that the above-mentioned PET layer is applied to either the front surface or the back surface of the above-mentioned hologram layer, and the other surface of the hologram layer is applied to the first or second transparent member.
In this case, the hologram film is preferably applied to the transparent member less likely to be damaged based on the condition of use, and the like. For example, the hologram screen can be constructed using the side to which the hologram film is not applied as the side more likely to be damaged, for example, as the side facing observers.
With such a construction, the first or second transparent member that is disposed on the side more likely to be damaged, can be replaced to reuse the hologram film.
Next, according to an eleventh aspect of the present invention, the above-mentioned anti-contact agent is preferably spherical, cylindrical or scale-like in shape.
With such a construction, a gap is securely provided between the hologram film and the first or second transparent member, and sticking between them can be reliably prevented.
Next, according to a twelfth aspect of the present invention, the above-mentioned anti-sticking agent is preferably formed from inorganic material including, as a principal component, silicon dioxide, borosilicate glass, or aluminum oxide, plastic materials including, as a principal component, divinylbenzene or methyl ester methacrylate, or starch such as grape sugar, cane sugar.
With such a construction, sticking between the hologram film and the first or second transparent member can be reliably prevented.
Next, according to a thirteenth aspect of the present invention, the above-mentioned anti-sticking agent can be formed in powder form and be applied with a brush to the first transparent member, the second transparent member, or the hologram film.
With such a construction, the anti-sticking agent can be interposed easily and reliably between the hologram film and the first or second transparent member.
Next, according to a fourteenth aspect of the present invention, the anti-sticking agent can be formed in an aqueous suspension and be applied by spray coating to the first transparent member, the second transparent member, or the hologram film.
Also in this case, the above-mentioned anti-sticking agent can be interposed easily and reliably between the hologram film and the first or second transparent member.
Next, according to a fifteenth aspect of the present invention, the above-mentioned anti-sticking agent can be formed in aqueous suspension and be applied by spin coating to the first transparent member, the second transparent member, or the hologram film.
Also in this case, the above-mentioned anti-sticking agent can be interposed easily and reliably between the hologram film and the first or second transparent member.
Next, according to a sixteenth aspect of the present invention, the above-mentioned anti-sticking agent can be suspended in an alcohol solution and be applied by spin coating to the first transparent member, the second transparent member, or the hologram film.
Also in this case, the above-mentioned anti-sticking agent can be interposed easily and reliably between the hologram film and the first or second transparent member.
Next, according to a seventeenth aspect of the present invention, sealant material for preventing uneven contact is preferably interposed uniformly both between the hologram film and the first transparent member and between the hologram film and the second transparent member.
When the hologram film and the first or second transparent member are of such a material property that the contact is likely to become partial (uneven), the above-mentioned sealant material may be interposed between the hologram film and the first transparent member and between the hologram film and the second transparent member, respectively.
With such a construction, there is no gap between the hologram film and the first and second transparent members, respectively, and close contact over the entire surface without uneven contact can be achieved. Degradation of image quality due to the partial contact between the hologram film and the first or the second transparent member can be thereby prevented. Also, in the state in which images are not being regenerated, the good design and appearance of the hologram screen can be maintained. The sticking force of the sealant material with the first and the second transparent members is preferably such that an operator can manually separate the hologram screen from the transparent member with ease.
Next, according to an eighteenth aspect of the present invention, the above-mentioned sealant material is preferably glycerin, triethanolamine, or alcohols having a high boiling point such as ethylene glycol.
With such a construction, close contact between the hologram film and the first and the second transparent members can be achieved reliably and, when replacing the transparent member, the hologram screen can be easily separated from the transparent member.
Next, according to a nineteenth aspect of the present invention, a release agent may be coated on the entire front and back surfaces of the hologram film, and an adhesive layer may be provided via the release agent. Also, on the front and back surfaces, the first and the second transparent members which are larger than the hologram film are respectively applied with the first and the second transparent members being adhered to each other with an adhesive at the portion outside of the periphery of the hologram film.
By coating the above-mentioned release agent, even if the first and the second transparent members which are larger than the hologram film are adhered with an adhesive, the first and second transparent members are not adhered to the hologram film. Thus, the first and the second transparent members are adhered to each other only at the portion outside of the periphery of the hologram film.
Therefore, when the first or the second transparent member is damaged and needs to be replaced, only by cutting and removing the adhered portion, one can take out the hologram film easily with no damage, and use the hologram again.
As the above-mentioned release agent, silicone, for example, may be employed.